In a photolithography process of a manufacture process for a semiconductor device, various process liquids such as a resist are fed to a substrate such as a semiconductor wafer (hereinafter, simply referred to as a wafer).
Referring to FIG. 15, a liquid bottle 101 storing a resist 101 is provided with a resist feed mechanism 102 that is attachable to and detachable from the liquid bottle 101. The resist feed mechanism 102 includes a bottle cap 104 for closing an opening 103 of the liquid bottle 101. A pressurizing gas such as a nitrogen (N2) gas is fed into the liquid bottle 101 through a pressurizing gas feed tube 105 provided in the bottle cap 104. As a result, the resist 110 flows into a process liquid feed tube 106 with a lower end thereof submerged below a liquid surface and then is pressure-sent to the wafer. If the resist is exhausted and decreases, the liquid bottle 101 is replaced.
A lock mechanism 107 for fixing a height position of the process liquid feed tube 106 is provided on an underside of the bottle cap 104. The lock mechanism 107 is a ring-shaped member with a thread around its periphery. The lock mechanism 107 is configured to increase friction between its inner periphery and the process liquid feed tube 106 as being fastened to the bottle cap 104, thus anchoring the process liquid feed tube 106 to the bottle cap 104.
In general, the resist 110 is expensive. Thus, it is preferred that the liquid bottle 101 is replaced after the resist 110 in the liquid bottle 101 is fully used. Further, to this end, it is necessary to adjust the height position of the process liquid feed tube 106 such that the lower end of the process liquid feed tube 106 is placed in contact with a bottom surface of the liquid bottle 101. In this regard, the bottle cap 104 may be attached to the liquid bottle 101 through the following procedures.
First, the resist feed mechanism 102 is attached to the liquid bottle 101 as locking caused by the lock mechanism 107 is released. The height of the process liquid feed tube 106 is adjusted in order to find a position where the lower end of the process liquid feed tube 106 abuts against the bottom surface of the liquid bottle 101. Subsequently, the bottle cap 104 is removed from the liquid bottle 101 such that the process liquid feed tube 106 and the bottle cap 104 are not shifted relative to each other. Thereafter, the process liquid feed tube 106 is locked to the bottle cap 104 by means of the lock mechanism 107. After locking, the bottle cap 104 is attached to the liquid bottle 101 again.
However, the experience or skill of the operator, who carries out the replacement task, may influence whether the relative position between the process liquid feed tube 106 and the bottle cap 104 can be maintained accurately until the height position of the process liquid feed tube 106 is found and then locked into position. Furthermore, to prevent the deterioration of the resist 110 within a process atmosphere of a clean room where the liquid bottle 101 is situated, the liquid bottle 101 includes a lightproof member. Thus, it is impossible to visibly identify the position of the lower end of the process liquid feed tube 106 in the liquid bottle 101 outside the liquid bottle 101. As a result, although the operator locks the process liquid feed tube 106 through the aforesaid procedures, the lower end of the process liquid feed tube 106 may be spaced apart from the bottom surface of the liquid bottle 101 in practice. Thus, some of the resist 110 may remain in the liquid bottle 101 (i.e. due to the space between the lower end of the process liquid feed tube 106 and the bottom surface of the liquid bottle 101).
Further, the liquid bottle 101 may include a highly transparent member depending on the type of process liquid being used. However, the process liquid may be lightproof, and in such a case, it is impossible to identify the position of the lower end of the process liquid feed tube 106 outside the liquid bottle 101. Therefore, the lower end of the process liquid feed tube 106 may spaced apart from the bottom surface of the liquid bottle 101.
According to the resist feed mechanism 102 shown in FIG. 15, the lock mechanism 107 performs a locking action at the underside of the bottle cap 104. However, by way of another example, the lock mechanism may be configured to perform the locking action on top of the bottle cap 104. In such a case, the locking action can be performed as the bottle cap 104 is attached to the container body 101. However, this is problematic in that screw-fastening of the lock mechanism 107 may shift the position of the process liquid feed tube 106 downwardly and a lower end portion of the process liquid feed tube 106 may be bent using such a process. Accordingly, the operator needs to perform the locking task while raising the process liquid feed tube 106 to the extent that the positional shift is caused by the screw-engagement. However, this may also lead to leaving some of the process liquid remaining in the container body 101 since properly positioning the liquid feed tube 106 varies depending upon the experiences or skills of each operator.
Moreover, the liquid bottle 101 has various shapes and thus the positional adjustment of the process liquid feed tube 106 as explained above must be made whenever replacing the liquid bottle 101, but this is burdensome. Japanese Laid-open Patent Publication No. 2008-6325 suggests one example of the above-explained process for liquid feed mechanisms. However, this reference is silent as to the afore-mentioned problems and the mechanism suggested therein cannot solve the problems. Further, Japanese Laid-open Patent Publication No. (Sho) 60-251047 suggests a structure of a handle cap. However, the handle cap suggested in this reference is used for a gasoline tank. The handle cap is irrelevant to the present disclosure and cannot solve the afore-mentioned problems.